Lumens to Watts Calculator — Convert Light Bulb Brightness to Power Consumption

Lumens to Watts Calculator

Convert lumens to watts for LED, incandescent, halogen, and CFL bulbs. Understand lighting efficiency and calculate energy savings when switching bulb types.

Step 1: Brightness Input

800 lm

Understanding Lumens

Lumens measure the total amount of visible light emitted by a source. Higher lumens mean brighter light. Modern LED bulbs produce more lumens per watt than traditional incandescent bulbs.

Step 2: Bulb Type & Efficiency

4 hours

About Bulb Efficacy

Efficacy measures how efficiently a bulb converts electricity to light (lumens per watt). LED bulbs typically have 80-120 lm/W, while incandescent bulbs only have 10-17 lm/W.

Conversion Results

Summary
Bulb Comparison
Energy Analysis

Equivalent Wattage

8 W
Efficacy: 100 lm/W
Energy Consumption
0.032 kWh/day
Daily Cost
$0.005
Annual Cost
$1.75
vs Incandescent
85% Less

Bulb Type Comparison

Bulb Type Typical Efficacy Wattage Needed Annual Cost* Lifespan

*Based on 4 hours daily usage at $0.15/kWh

Energy Consumption Analysis

Lumens to Watts Formula

Watts = Lumens ÷ Efficacy (lm/W)

The wattage needed is calculated by dividing the desired brightness in lumens by the bulb’s efficacy (lumens per watt). Higher efficacy means less wattage is needed for the same brightness.

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